1. Field of the Invention
The present invention relates to an appreciation data correction method and an appreciation data correction apparatus for carrying out aesthetic processing such as image processing on appreciation data such as image data and audio data. The present invention also relates to a computer-readable recording medium storing a program that causes a computer to execute the appreciation data correction method.
2. Description of the Related Art
There have been known systems for appreciation of images and music without constraints on time and place. In such a system, image data obtained by photographing a subject with a digital camera or a digital camcorder or audio data obtained by privately recording a music performance are stored in a server after the data are transferred to the server via a public communication line. The data are transferred to an apparatus for reproducing the data whenever needed. By using such a system, a person who privately recorded the data can appreciate the image data or the audio data either alone or with family members and friends thereof. The data can be reproduced in the system by the reproduction apparatus of various models, such as a reproduction apparatus that directly reproduces the data (a cellular phone, a digital TV set, a game terminal, an electronic photo frame, a personal digital assistant (PDA), an in-vehicle terminal, an outdoor large-screen display, a head mount display, and a retinal projection display), by a reproduction apparatus dedicated to reproducing the data that have been recorded in a recording medium (a CD-R, a DVD, an MD, and a Memory Stick), by a printer that reproduces the image data as a hard copy, and by an automatic performance instrument that automatically reproduces the audio data.
Meanwhile, there has been known a system for appreciation of images by using an output device such as a printer or a monitor that reproduces image data obtained by an imaging device such as a digital camera or a digital camcorder, or image data obtained by reading images recorded on a photographic film with a scanner. In such a system, in order to improve quality of the images reproduced by the system, image processing of various kinds is carried out on the image data.
For example, there has been proposed a method of improving quality of a reproduced image by carrying out image processing such as edge enhancement and contrast enhancement on image data read from a photographic film, based on photography information obtained at the time of photographing, such as information on a photographing distance, serial photographing, flash emission, shutter speed, and subject luminance (Japanese Unexamined Patent Publication No. 7(1995)-159904).
Furthermore, since each human face attracts the most attention in an image, a method of changing degrees of edge enhancement processing and tone processing in accordance with presence/absence and a size of a face area recognized in the image has also been proposed (Japanese Unexamined Patent Publication No. 9(1997)-233423).
Moreover, a method of obtaining a reproduced image in appropriate color balance has also been proposed (Japanese Unexamined Patent Publication No. 9(1997)-181918). In this method, a representative value representing a characteristic of a photographic film (such as a reference value on a high-density side or on a low-density side) is found for each of image data sets representing images recorded in the photographic film and a condition for converting the image data sets is determined based on the representative value.
Another method of compensating a difference in characteristics of imaging devices has also been proposed. In this method, a device characteristic such as a color reproduction characteristic or a tone reproduction characteristic is found for each imaging device by photographing a color chart with the imaging device, and correction that is appropriate for the device is carried out on image data based on information related to the model of the imaging device attached to the image data as tag information.
However, a wide variety of imaging devices are in use, and new models come on the market everyday. Therefore, finding the device characteristic for each of the imaging devices available on the market requires a vast labor force. Furthermore, since the device characteristic changes with a photographing condition such as AE/AWB setting, appropriate image correction for all photographing conditions is substantially difficult.
Meanwhile, each viewer appreciates a color in an image, such as a skin color or a color of the sky or foliage, indifferent manner, depending on memories and a childhood environment of the viewer, for example. Therefore, preferable colors, that is, a preferable image quality varies between viewers. If image data are corrected by the method described in Japanese Unexamined Patent Publication No. 7(1995)-159904, for example, an image represented by the image data can be corrected comparatively well on average. However, it is rare for all viewers to be satisfied, and the image may not be preferable for some of the viewers. For this reason, if a user wishes to obtain the image in a quality satisfactory for him/her when the corrected image data are printed, the user needs to correct the image again by notifying a color correction instruction or the like to a printing agency or the like after viewing the print. As a result, acquisition of optimal quality image is time-consuming.
In the case where the image is displayed on a monitor, correction of the image data by adjusting a color correction control of the monitor or by manual correction is necessary. However, this correction requires experience and correction for optimal image quality is difficult. Since a wide variety of monitors are also available and new models come to the market everyday, satisfactory image correction regarding a quality of an image displayed on one monitor may not necessarily be satisfactory for the same image displayed on another monitor.
As has been described above, since a troublesome operation is necessary for reproduction of image data in an optimal quality, a user has to accept the image even if the image is not ideal for the user.
In the above system for appreciation, the data are stored in their original forms, and format conversion such as enlargement/reduction (in the case of image data) or DA conversion (in the case of audio data) is carried out in accordance with a format of the reproduction apparatus. However, the data after the format conversion may not necessarily appropriate for appreciation.
In the case of audio data recorded privately, the audio data are rarely appreciable due to a recording level being too high or too low or fluctuating, or due to a noise or unnecessary sounds. Therefore, processing for causing the audio data to become appreciable has been desired.